Calculating machine



Jan. 12,' 1932. c. WITTENMYER 7 1,840,378

CALCULATING MACHINE Filed Oct. '27, 1926 INVENTOR.

Q41 ma ATTORNEY.

Patented Jan. 12, 1932 UNITED STATES CARLOS WI'ITENM'YER, OF MOUNT CLEMENS, MICHIGAN CALCULATING MACHINE Application filed October 27, 1926. Serial No. 144,411.

The present invention relates to calculating machines and particularly to improvements in machines of the type shown in the U. S. patent to Felt 767,107 August 9, 1904.

In machines of this type when used for subtraction the method consists in adding the complement of the subtrahend and preventing a carry. It is therefore, the practice to provide, for machines of this character, a subtraction lever which is set only when a carry will result. Accordingly, the subtraction operation requires the use of both hands, one to hold the subtraction lever in operative position to prevent a carry and the other to strike the desired number keys. This is frequently inconvenient if not impossible as one hand may be necessary for another use at the time.-

An object of the present invention, therefore, is means to lock the subtraction lever in its set position, so that the operation of subtraction may be carried out using only one hand, this hand being used first to move the subtraction lever to its set position where it will be automatically locked and then to operate the desired key.

Another object is means to automatically or otherwise lock said lever in operative or carry foiling position to prevent the carry and to unlock said lever after the carry has been attempted and foiled.

Other objects will readily appear to those skilled in the art upon reference to the accompanying drawings in which Fig. 1 is a view in elevation of the carrying mechanism and subtraction lever with the latter in operative position;

Fig. 2 is a view of a portion of the same mechanism showing the mode of release;

Fig. 3 is a perspective View of the locking device.

The device embodying the invention is to be used in conjunction with the present known subtraction mechanism which is shown in the drawing. Referring to the drawings is one of the number wheels constructed in the usual fashion while 11 is the carrying pawl pivoted at 12 on a bell crank 13 operable by mechanism (not shown) 0 to swing about point 14 in counter-clock wise direction. Lever 13 also carries the 1 locking detent 15 pivoted at 16. These parts each operate as in the patented mechanism to carry over from one denomination row to the next number wheel.

The subtraction lever is shown at 20, pivoted to the frame (not shown) at 21. This lever has at its upper end a finger piece 22 projecting out of the machine so that it may be operated. The lower end has, like the 60 known form, a forwardly projecting cam portion 23 upon which the lower end of pawl 11 strikes when said lever is in the carry preventing position as in Fig. 1. When in this position pawl 11 cannot perform its carry function because its upper end is held away from the wheel.

In the known machine, as the lever is held in inoperative position by a small spring 24 it is necessary to maintain a pressure on finger piece 22 to hold the cam end 23 in the path of the end of pawl 11.

In the present improvement when the cam end 23 is ignoved forward by pressure on the finger piece 22. it is locked in its forward position until the movement of the carrying pawl 11 is about completed when it is released. The release. however, is accomplished too late for the wheel 10 to be moved.

This locking action is accomplished by the 80 piece which is pivoted at 31 on a suitable frame portion 32 provided with a stop piece 33 against which abuts a shoulder 34 formed on the lock piece. This piece 30 is provided with an arm 35 arranged to be substantially horizontal when shoulder 34 is against stop 33 and having at its outer end a locking shoulder 36 adapted to drop over and hold a pin 37 on a suitable portion of the lower part of lever 20. This piece 30 is normally held down by a small spring 38 and, when lever 20 is in inoperative position, rests on pin 37. Whenever, therefore, the lever end 23 is moved forward to operative position the shoulder 36 drops behind the pin 37 and locks i the lever forward. 4

The unlocking is accomplished by providing an arm 40 extending upward and forward and having its outer end bent over laterally as at 41 to extend into the path of the end 42 of 100 the detent 15 which engages end 41 a suificient distance before the end of its travel to lift shoulder 36 from pin 37. \Vhen this takes place, spring 24 immediately returns lever 20 to its inoperative position.

Having now described the invention and the preferred form of embodiment thereof, it is to be understood that the said invention is not to be limited to the specific details herein described and shown but only by the scope of the claims which follow.

I claim 1. In a calculating machine, of the type having a plurality of rows of keys representing different denominations, a number wheel for each row, and mechanism for carrying from one wheel to the next higher in order, a lever for temporarily toiling the carrying mechanism, and means for locking said lever in foiling position during the movement of the carrying mechanism.

2. In a calculating machine of the type havin a plurality of rows of keys representing difierent denominations, a number Wheel for each row, and mechanism for carrying from one wheel to the next higher in order, a lever for temporarily foiling the carrying mechanism, and means for locking said lever in foiling position during the movement of the carrying mechanism, and means for unlocking said lever after the carrying movement has been foiled.

3. In a calculating machine including multiple order calculator mechanisms, automatic carrying mechanisms, and subtraction levers for eliminating the carrying on the part of the individual carrying mechanisms; means for holding each actuated subtraction lever in operative relation to prevent the carrying on the part of the individual carrying mechanisms, and means for resetting said subtraction levers in inoperative relation.

f1. In a calculating machine including multiple order calculator mechanisms, automatic carrying mechanisms, and subtraction levers for eliminating the carrying on the part of the individual carrying mechanisms; means for holding each actuated subtraction lever in operative relation to prevent the carrying on the part of theindividual carrying mechanisms, and means actuated by the individual carrying mechanisms for resetting said subtraction levers to inoperative relation.

5. In a calculating machine including multiple order calculator mechanisms, column actuators, automatic carrying mechanisms each including a pawl, and subtraction levers for disengaging the pawls of the individual carrying mechanisms for the purpose of eliminating the carrying on the part of the individual carrying mechanisms; means for holding each actuated subtraction lever in operative relation to hold the corresponding carrying mechanism pawl in disengaged relati on for preventing the carrying on the part of the individual carrying mechanisms and means for reset-ting said subtraction lovers in inoperative relation.

6. In a calculating machine including multiple order calculator mechanisms, column actuators, automatic carrying mechanisms, and subtraction levers for eliminating the carrying on the part of the individual carrying mechanism; pivoted levers for locking each actuated subtraction lever in operative relation to prevent the carrying on the part 0 if the corresponding carrying mechanism and means for resetting said subtraction levers in inoperative relation.

7'. In a calculating machine including multiple order calculator mechanisms, column actuators, automatic carrying mechanisms, and subtraction levers for eliminating the carrying on the part of the individual carrying mechanisms, pivoted levers for locking each actuated subtraction lever in operative rela tion to prevent the carrying on the part of the individual carrying mechanisms, each lever being so shaped as to be returned by the operation of the corresponding carrying mechanisms to inoperative position to release the corresponding locked subtraction lever.

CARLOS WITTENMYER.

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